1. Field of the Invention
This invention generally relates to the field of communications and more particularly to systems and methods for providing secure and private communications over a digital network, including session protection privacy, private remote data storage of data and user access control over such remotely stored private data.
2. Description of the Related Art
It is well known that individuals using telecommunications networks are continuously exposed to compromises of their privacy. This issue has become particularly acute with respect to the Internet. In many cases Internet hosts, service providers and Web sites can link users with their identities, and track and create databases of their activities. Voluntary privacy policies and related certification organizations such as Truste® have imposed some limits on Internet privacy abuses, but do not by any means assure end user privacy or anonymity.
As shown in FIG. 1, a client system 100 is connected over a telecommunications link 110 to an Internet Service Provider (ISP) (not shown) and ultimately to the Internet 150. A Web server (Third-Party HTTP server 160) is connected over its own link 161 to the Internet 150. Properly addressed Internet Protocol (IP) packets may be exchanged over the Internet 150 between client 100 and Web server 160. FIG. 1A shows the layout of a typical IP packet, including a header 191 containing, among other information, a source address 192 and a destination address 193, as well as data portions, 194, 195, comprising, in this example, 452 “octets” (bytes) of data.
Client system 100 runs Web browser software 105 which establishes a display window visible to the user. Web browser 105 submits an http request 125 over the internet. The IP packet containing request 105 contains a header that is encoded with the IP address of client 100. Furthermore, Web server 160 may have previously given a “cookie” to client 100, containing information regarding the user of client 100. Information from this cookie may also be encoded as data within the IP request. Thus, when Web server 160 receives http request 125, it may acquire considerable identity information regarding the user, and will of course further have complete information about the action requested by the http request. The correlation of action and identity is particularly valuable to marketers, yet at the same time most threatening to users when in the hands or people outside their confidence and control.
Web server 160 parses the http request, and processes it, serving up the Web page requested by the user, and/or conducting further processing via a “common gateway interface” (CGI) 185, which in turn may invoke further processing via scripts and programs 180, which may in turn communicate with databases such as database 190 and/or other facilities. The requested information is sent back to client 100 by http response 175, again encoded in addressed IP packets and sent to client 100 over the Internet 150. Web browser software 105 receives the http response 175 and from it creates the appropriate screen displays or multimedia effects for the end user.
The system commonly used in the prior art to provide some means of isolating an end user from total exposure to the Internet is known as a “fire-wall” or “proxy server”. Proxy server 140 is shown in FIG. 1 as an optional addition to a prior art Internet communication system. Web browser software 105 is adjusted through a setup or configuration facility to direct and receive IP packets in the first instance from proxy server 140, instead of the usual router, gateway or similar facility of the ISP. Proxy server 140 can then intermediate, and thereby filter undesired or unacceptable input or output (which may be so deemed for any number of reasons, including security and censorship, in addition to privacy), and can also reconstruct IP packets so as to some extent mask the user's identity. However, the operator of the proxy server can readily retrieve, and perhaps secretly misuse, any of this information. Therefore, to be effective, the end user must trust the administrator of the proxy server in question. In a commercial setting, and most particularly in a mass market setting, establishing and maintaining such trust in an entity may not be practicable.
Another set of privacy-related systems that has been deployed to a limited extent are “anonymous remailers”. These use various techniques to separate the body of an email message from its identifying header and to resend it the intended recipient under the remailer's headers. The difficulty with such systems, such as the well-known remailer at anon.penet.fi in Finland, is that the server administrator has access to both the identity and content information, rendering it vulnerable to abuse or disclosure. In the case of anon.penet.fi, the disclosure was forced by a subpoena obtained by the Church of Scientology and enforced in Finland, which required the server administrator to hand over records of communications from a user that were the subject of a lawsuit by the Church against the user.
Other systems for protecting end user privacy have been developed. Typically such systems involve setting one or more proxies in series either locally on an end user's computer or on one or more servers. Such systems generally provide privacy protection by masking the identity of the sender from third party servers.
For example, one system, Crowds, which was developed by AT&T, enhances privacy by sharing http requests randomly among a group of subscribed users. With Crowds, although the identity of a request sender can trace the identity of a request sender to the group of users, the third party cannot be traced to any specific user.
Various cryptographic methods, including but not limited to public-private key cryptography, symmetric key cryptography, one-way hash cryptography, have been used for privacy-enhancing purposes. Such methods have been applied in one system, Zero Knowledge, to provide anonymity by encapsulating identity information in encrypted form in a surrounding packet created by an intermediate or proxy server. However, in such a system, the operators of the intermediate or proxy server have access to both identify and action information, and could compromise that information or be forced to give it up to governmental or private parties by subpoena or other legal process.
Other systems have used cryptographic techniques to provide for encrypted remote data storage. In such approaches, data is typically sent to server through protected channel such as Secure Socket Layer (SSL) connection. On receipt of data at server, server generates cryptographic key and stores the data. The result of such systems is that data is protected in transit and while stored. However, such systems still suffer from the drawbacks that the identity of end user is known to storing server, and that the contents of stored data are known to storing server just prior to the data being encrypted for local storage.
Systems that have provided access control for remotely stored data have generally followed the following model:                A data is request sent to server through protected channel such as Secure Socket Layer (SSL) connection; and        On receipt of the data request at the server, the server checks the request against secondary access control system that contains an index of data objects, users, and associated access privileges.        
The result of such a system is that data requests are protected in transit and data requests can be controlled according to access rights on the server. However, such a system has the drawbacks that (i) the identity of end user is known to server; (ii) the contents of stored data are known to server; and (iii) the data request is known to server. The result is that such systems do not provide for strong protection of user identities or stored data. Managers of such systems can easily obtain any and all information passing through the system, as can malicious attackers.
The system disclosed here provides greater security than prior solutions. The system described here goes beyond masking the identity of the sender from third parties and masks the identity of the sender from both third parties and the system itself. This masking is accomplished by separating action from identity on the client computer. By way of comparison, while the Crowds system prevents third-parties from knowing the identities of senders, the Crowds system itself, and the other systems discussed above, have the ability to know both the identity and actions of its users. The greater security provided by the system has the additional benefit of enabling more personal communications to be sent through the system. Because the system does not rely on removing identifying information for its functionality, end users can receive the benefits of identity protection without sacrificing the ability to act as individuals rather than anonymous entities.